1. Field of the Invention
The present invention relates to an intermediate transfer substance for thermal transfer printer, being capable of speedily recording a high-quality image on a recording medium such as plain paper or bond paper.
2. Description of the Prior Art
Conventional thermal transfer printers have generally been configured such that the molten ink on the ink ribbon is softened on the thermal head to transfer the ink for recording on a recording medium such as paper.
So as to effect high-quality image recording (printing) by such general thermal transfer printers, specific recording media of smooth surface have been used.
So as to effect high-quality image recording with no defect such as void on inexpensive recording media with larger irregularity on the surface, such as plain paper and bond paper, in recent years, a thermal transfer printer of intermediate transfer type has been proposed, wherein the ink on the ink ribbon is melted via exothermic heat from the thermal head and is once thermally transferred and recorded onto an intermediate transferring medium with silicone rubber surface in the form of roll or belt, to write the ink image (primary record image) on the intermediate transferring medium. Then, the ink image written on the intermediate transferring medium is re-transferred on a recording medium.
The intermediate transferring medium to be used for the thermal transfer printer of such intermediate transfer type should be imparted with the property to be written via ink during recording so as to write the ink image and the property of re-transferability during re-transferring so as to re-transfer the ink image on a recording medium. During re-transferring in particular, the intermediate transferring medium should have higher surface releasability.
As disclosed in Japanese Patent Laid-open No. Hei 5(1993)-338368, an intermediate transferring medium has been proposed as one of conventional examples to satisfy such demand, having a transfer layer produced by adding a releasing agent such as dimethyl silicone oil, reactive silicone oil for amino modification or epoxy modification, and carnauba-modified silicone oil solid at 100.degree. C. or less into silicone rubber so as to improve the releasability of silicone rubber.
Such intermediate transferring medium with the transfer layer formed from the silicone rubber into which such conventional releasing agent have been added has improved ink releasability and thus effects high-quality image printing on recording media such as plain paper and bond paper, compared with the intermediate transferring medium with a transfer layer formed from general silicone rubber.
Such conventional intermediate transferring medium has excellent effects such that the substance can securely retain the re-transferability during re-transferring for a long term, and additionally, the substance can effect printing of high-quality image on recording media such as plain paper and bond paper with larger irregularity. Furthermore because the transfer pressure during re-transferring can be set low, the size and structural strength of a thermal transfer printer using the intermediate transferring medium can be reduced, concurrently, which very effectively reduces the size and cost of the thermal transfer printer.
So as to confer better performance, recently, thermal transfer printers have been consistently improved. As the thermal transfer printers have got better performance, an intermediate transferring medium for such printers should be required to securely retain the potency to be written via ink during recording so as to write the ink image and the re-transferability during re-transferring of the ink image on a recording medium, for a long term.